This invention relates in general to conveying systems for moving quantities of granular, pulverized or fluid material from one point to another and, more particularly, to systems in which the feeding member is helical in form.
Conveying systems comprising rotating helical means encased in a long flexible tube are well-known in the prior art, as disclosed, for example, in U.S. Pat. No. 3,381,801 issued May 7, 1968 to B. Rastoin, in which a flexible core is disposed within the rotating helix in fixed axial relationship to the enclosing flexible tube. Such systems are used, for example, for filling freight cars or trucks with pulverized coal or grain from stockpiles of the same, or for conveying such materials from one point to another during processing.
A system of the type disclosed by Rastoin has the disadvantage that a portion of the material to be conveyed tends to fall down between the rungs of the rotating helix, causing a loss in efficiency of the system. Moreover, it may be fairly expensive to manufacture a flexible tube including a fixed axial core of the type required by Rastoin. In addition, operation of the system requires constant monitoring to prevent the output container from overfilling.